21 #ifndef __JackLoopbackDriver__    22 #define __JackLoopbackDriver__    24 #include "JackAudioDriver.h"    38         virtual int ProcessReadSync();
    39         virtual int ProcessWriteSync();
    41         virtual int ProcessReadAsync();
    42         virtual int ProcessWriteAsync();
 
Locked Engine, access to methods is serialized using a mutex. 
Inter process synchronization using POSIX semaphore. 
The base class for audio drivers: drivers with audio ports. 
The loopback driver : to be used to "pipeline" applications connected in sequence.